The protein composition and surface characterization of intact Trichomonas vaginalis will be performed for identification of highly antigenic and exposed proteins. Laboratory animals will be evaluated as models for establishment of subcutaneous, intravaginal, and intraperitoneal infections and immune (IgG) responses monitored using highly sensitive and specific technologies in order to identify immunologically significant antigens. Numerous isolates of pathogenic T. vaginalis including trichomonads sensitive and resistant to metronidazole will be used in this study. Clone isolation will be attempted and trichomonads analyzed for surface protein composition and virulence as measured by the ability to establish infection using the mouse model. Hybrid cells producing antibody against trichomonal antigens will be produced and antibody compared with monospecific antiserum from rabbits immunized with defined protein preparations. Affinity purification of membrane proteins will be accomplished, and purified materials evaluated as single or multicomponent vaccinogen candidates or immunodiagnostic reagents. Consistent with the above approaches will be employment of trichomonal antigens or antibody to evaluate binding of clones to monolayer cultures of cell culture systems for implicating ligands on trichomonal surfaces responsible for parasitism of vaginal epithelium. Analysis of antibody properties directed at T. vaginalis such as agglutination, complement-fixing, or cytotoxic abilities will be investigated.